Semester One Exam Flashcards
What is the difference between physical and a chemical change?
A physical change consists of only changing physical properties while a chemical change results in an entirely new chemical.
What is the difference between reactants and products in a chemical reaction?
reactants - addends (left side of equation)
products - what the addends yield (right side of equation)
How do you know the difference between a physical and a chemical change?
a chemical change will result in a different chemical structure
What is a metal and where is it on the period table?
High electrical and thermal conductivity
Malleability
Ductility
High reflectivity of light
left of the staircase
What is a nonmental and where is it on the period table?
Lack all the metallic attributes.
Are good insulators of heat and electricity.
Are mostly gases, sometimes liquids, and occasionally solids at room temperature.
Do not display the properties of metals, such as being malleable, ductile, or good conductors of heat and electricity
right of the staircase
What is a metalloid and where is it on the period table?
semiconductors
brittle solids
staircase
(Boron, Silicon, Germanium, Arsenic, antimony, Tellurium, Polonium, Selenium, Astatine)
What is the difference between qualitative and quantitative?
qualitative - quality (just normal adjectives)
quantitative - quantity (numbers)
What is the difference between precision and accuracy?
Precision - how close each measurement is to all of the other measurements
Accuracy - how close each measurement is to the correct value / goal
What is the Law of Definite Proportions?
The fact that a chemical compound contains the same element in exactly the same proportions by mass regardless of the size of the sample or source of the compound.
What is the nucleus of an atom?
A region in the center of an atom that is positively charged and consisted of positively charged protons and neutrons of no charge.
What is the location of an electron?
The electron cloud
What is the charge of an electron?
-1
What is atomic number?
The number of protons in one atom of an element
What is mass number?
The sum of all the particles in and atom of the average isotopes. Electrons are so small that you do not count them, so it is the sum of protons and neutrons. Because isotopes exist, neutrons are an average.
What are isotopes?
Atoms with a different number of neutrons than protons.
How do isotopes relate to mass number and neutrons?
The sum of all the particles in an atom of the average isotopes is mass number. Electrons are so small that you do not count them, so it is the sum of protons and neutrons. Because isotopes exist, neutrons are an average.
What was Louis de Brogle’s contribution to the quantum model?
He created the duality theory which states that electrons behave both like particles and like waves.
What do quantum numbers describe?
The character of an electron
What are the four quantum numbers and what do they describe?
- Principle - shell
- Angular - shape (spdf)
- Magnetic - orientation
- Spin - spin
Know how to do electron configuration and what it means
Know how to do electron configuration and what it means
Based on period law, explain which elements are most similar given three elements.
What factors may cause atoms to be similar?
Electronegativity
Nonmetal, metal, or metalloid
Group
Period
Number of Valence electrons
Ionization energy
Why do atoms form chemical bonds?
Atoms want to have a full valence shell so they react with other atoms so that they can have a full valence shell. This causes chemical bonds.
Use examples to show how properties and classifications of elements change as you move across a period.
Going left to right across a period, what changes?
Atoms get smaller because they have more protons and electrons that are pulling on each more strongly and causing the atom to be smaller
Electronegativity goes up (how much the atom attracts electrons)
Ionization energy goes up (force it takes to remove an electron)
*Going from top to bottom in a group it becomes easier to remove an electron (ionization energy) (this is because there are more shells between the protons and electrons so the pull on each other is not as strong and it is easier to lose electrons)
Explain nuclear charge and how it affects the general trend in radii of atoms going from left to right across the periodic table.
Atoms get smaller because they have more protons and electrons that are pulling on each more strongly and causing the atom to be smaller
What is Avogadro’s number?
6.022 x 10^23 atoms per mole
How do you convert moles to grams?
When given the amount of an element in moles, multiply by the atomic mass of that element (already in grams) all over one mole.
Ex. What is the mass of 0.28 mol of iron?
0.28 mol Fe / 1g = 55.84g Fe / 1 mol Fe = 15.64g Fe
How does noble gas configuration work?
Start at the noble gas before the element you want and put the symbol in brackets. Then write the rest of the electron configuration.
How do the up down arrows work for an orbital diagram?
draw all of the up arrows first, then go back and add down arrows to create pairs. each letter of spdf… has a set of arrows
Using an orbital diagram, how do you determine what element you are looking at?
Look at the spdf… levels and see how many arrows are in the last letter.
Know how to create a Lewis dot structure for an atom and an ion.
Know how to create a Lewis dot structure for an atom and an ion.
ESSAY 1: How do properties of elements change when moving from left to right in a period? Use examples to support your answer (4-5 sentences).
-Moving from left to right there is one more proton and electron in each atom. This causes a stronger attraction between the proton and electrons causing the nuclear radii to be smaller as the particles draw closer to each other.
Ex. - Iron has one less proton and one less electron than Cobalt therefore Cobalt has a smaller nuclear radius because the particles are more attracted to each other and in return closer to each other.
-Increasingly less reactive until you get to the halogens
Ex. - Potassium is more reactive than Iron because of the number of valence electrons.
-Goes from metals to metalloids to nonmetals
Ex. - Potassium is a metal, Germanium is a metalloid, and Krypton is a nonmetal
-Electronegativity goes up (how much the atom attracts electrons)
Ionization energy goes up (force it takes to remove an electron)
ESSAY 2: What can you determine about an atom’s atomic structure if you are given its atomic number and atomic mass?
-Number of neutrons
~ = amu - # of protons
-What element it is
-Dictates period and group
-Dictates metal, nonmetal, or metalloid
-Number of protons
~ = atomic number
-Number of electrons
~ = atomic number
-Isotope average
~ =amu - # of protons
-Number of valance electrons
~ = atomic number separated by how many electrons go in each shell
-Dictates properties relative to the reactivity of the element
-Dictates what group number, number of shells, how malleable it may be, whether or not it is a good conductor or a semiconductor, electronegativity, atomic radii, ionization energy, etc.
